The present invention relates to a mechanism for tilting an outboard motor in a vertical plane relative to its mounting bracket and for holding the motor in and releasing it from selected tllt positions. More particularly, the invention pertains to a simplified tilt mechanism which provides automatic latching and return from intermediate tilt or trim positions and automatic latching in the uppermost or maximum tilt position.
Various outboard motor tilt mechanisms are disclosed in the prior art, all of which are intended to provide some combination of preset tilt positions, temporary movement from and return to the lower operating position, latching in an uppermost or maximum tilt position, and adjustment of the various positions. U.S. Pat. Nos. 4,331,430 and 4,472,148 describe similar mechanisms for providing a variety of outboard motor tilt positions. The positions typically include a series of lower trim positions, one or more shallow water drive positions, and an uppermost trailering position. These patents describe alternate mechanisms for selecting and establishing the various tilt positions and for moving the motor between them.
In U.S. Pat. No. 4,331,430, a tilt mechanism is described which includes a ratchet mechanism allowing the motor to be raised to a higher trim or shallow water position by simply tilting the motor about a horizontal axis and releasing it at the desired trim position. The motor may be returned to a lower trim position by tilting it beyond the highest trim or shallow water position, whereupon the ratchet mechanism engages a return cam surface which directs the return of the motor to its lowest trim position. An override lever may be manually engaged and held to temporarily disengage the ratchet mechanism while the motor is simultaneously being tilted, thereby allowing th emotor to be lowered without tilting to the highest position and utilizing the return cam surface.
The foregoing apparatus, though adequately providing the intended functions, is cumbersome and inconvenient to operate under certain conditions encountered in use. For example, direct automatic return of the motor from an upper trim position to its original lower operating position is not possible. The operator must either continue to tilt the motor up beyond the highest trim position and allow it to return via the return cam surface, or simultaneously engage a ratchet override lever while tilting the motor in an initial upward direction and allowing it to return directly down to the lower operating position. Both of the alternative procedures are awkward and somewhat cumbersome to undertake.
U.S. Pat. No. 4,472,148 provides an improvement to some of the functions in U.S. Pat. No. 4,331,430. Thus, the mechanism of U.S. Pat. No. 4,472,178 allows the operator to select and preset a number of lower operating or trim positions to which the motor will return directly when it is tilted down. However, the mechanism is subject to the same awkward and cumbersome operational aspects previously described. Also, both mechanisms are mechanically complex and require a substantial number of operating components.
U.S. patent application Ser. No. 178,564, filed Apr. 7, 1988, entitled "Tilt Mechanism for Outboard Motors", and assigned to the assignee of the present invention, discloses a tilt mechanism intended to correct the operational deficiencies in the two above described prior art mechanisms. Thus, the mechanism of Ser. No. 178,564 allows the operator to pivot the motor from any preset operating position temporarily to any higher position and still return directly to the original operating position Separate apparatus is also provided to allow the motor to be selectively moved to and held in a higher position, but such apparatus must be manually engaged and disengaged and requires the addition of another multi-part mechanism to the overall apparatus. Functional improvement is provided, but at the expense of additional complexity.
U.S. Pat. No. 4,637,800 discloses a more simplified tilt mechanism for an outboard motor which allows the motor to be tilted up from a lower operating position to a shallow water position where it may be locked and temporarily held. A separate manually operated control lever is used to either release the motor from its lower operating position for manual upward tilting or to release the motor from its upper shallow water position for manual return to the operating position. This mechanism includes no provision for intermediate step wise movement of the motor between the lower operating and intermediate upper trim, shallow water, or tilt positions.
The prior art is thus characterized by tilt mechanisms which attempt to provide a wide range of functions but are mechanically complex, and mechanically simple mechanisms which are very limited in the functions provided.